• Linus Walleij's avatar
    net: dsa: realtek-smi: Add Realtek SMI driver · d8652956
    Linus Walleij authored
    
    
    This adds a driver core for the Realtek SMI chips and a
    subdriver for the RTL8366RB. I just added this chip simply
    because it is all I can test.
    
    The code is a massaged variant of the code that has been
    sitting out-of-tree in OpenWRT for years in the absence of
    a proper switch subsystem. This creates a DSA driver for it.
    I have tried to credit the original authors wherever
    possible.
    
    The main changes I've done from the OpenWRT code:
    
    - Added an IRQ chip inside the RTL8366RB switch to demux and
      handle the line state IRQs.
    
    - Distributed the phy handling out to the PHY driver.
    
    - Added some RTL8366RB code that was missing in the driver at
      the time, such as setting up "green ethernet" with a funny
      jam table and forcing MAC5 (the CPU port) into 1 GBit.
    
    - Select jam table and add the default jam table from the
      vendor driver, also for ASIC "version 0" if need be.
    
    - Do not store jam tables in the device tree, store them
      in the driver.
    
    - Pick in the "initvals" jam tables from OpenWRT's driver
      and make those get selected per compatible for the
      whole system. It's apparently about electrical settings
      for this system and whatnot, not really configuration
      from device tree.
    
    - Implemented LED control: beware of bugs because there are
      no LEDs on the device I am using!
    
    We do not implement custom DSA tags. This is explained in
    a comment in the driver as well: this "tagging protocol" is
    not simply a few extra bytes tagged on to the ethernet
    frame as DSA is used to. Instead, enabling the CPU tags
    will make the switch start talking Realtek RRCP internally.
    For example a simple ping will make this kind of packets
    appear inside the switch:
    
    0000   ff ff ff ff ff ff bc ae c5 6b a8 3d 88 99 a2 00
    0010   08 06 00 01 08 00 06 04 00 01 bc ae c5 6b a8 3d
    0020   a9 fe 01 01 00 00 00 00 00 00 a9 fe 01 02 00 00
    0030   00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    
    As you can see a custom "8899" tagged packet using the
    protocol 0xa2. Norm RRCP appears to always have this
    protocol set to 0x01 according to OpenRRCP. You can also
    see that this is not a ping packet at all, instead the
    switch is starting to talk network management issues
    with the CPU port.
    
    So for now custom "tagging" is disabled.
    
    This was tested on the D-Link DIR-685 with initramfs and
    OpenWRT userspaces and works fine on all the LAN ports
    (lan0 .. lan3). The WAN port is yet not working.
    
    Cc: Antti Seppälä <a.seppala@gmail.com>
    Cc: Roman Yeryomin <roman@advem.lv>
    Cc: Colin Leitner <colin.leitner@googlemail.com>
    Cc: Gabor Juhos <juhosg@openwrt.org>
    Cc: Florian Fainelli <f.fainelli@gmail.com>
    Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    d8652956
realtek-smi.h 4.25 KB